It seems that pages-tef to docx conversion is not that different from standard pages to docx conversion and should be doable with existing Pages apps for MacOS or iOS. You probably cannot use any 3rd party program as .pages-tef files are not supported outside of standard Apple apps.
Convert Apple Pages iCloud document file to Microsoft Word Open XML document.
We have found one software suitable in our database for this conversion.
Apple macOS / Mac OS X software - convert pages-tef to docx on OS X
A word processor and layout tool marketed by Apple
Convert from pages-tef file format
|Yes, Pages for Mac supports docx file conversion as a target file type.||Yes||Yes||docx editor||Yes||No||No||No|
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.